1. Field of the Invention
The present invention relates to a printer for receiving and printing data and commands which are transferred from a data processing apparatus constituted as an external apparatus such as a host computer (including a word processor main body) or the like.
2. Related Background Art
Hitherto, in printers for printing data transferred from the host computer, the host computer produces software in which the printing mode, print pitch, line feed pitch, sheet feed amount and the like are changed in accordance with the object of the user. The host transfers the software together with the data, thereby obtaining a desired print output.
Namely, when the user wants to obtain various kinds of print output or wants to change a part of the previous print output format, or the like, the program of the host computer needs to be newly produced or the previous program needs to be newly made again.
For example, the software of the host computer must be changed in the following cases: the case where the data which previously was printed and output in the draft mode (the mode to print data for drafting in which the printing quality may slightly deteriorate) is now intended to be printed and output with a high quality in the NLQ (near letter quality mode, i.e., the printing mode or slightly higher quality), LQ mode (letter quality mode which is, the high quality printing mode), or the like; the case where the print pitch is changed from pica pitch (10 cpi) to elite pitch (12 cpi) in accordance with the change in print format or the like; or the case where the line feed pitch is changed from 1/6 inch to 1/8 inch; and the like.
With respect to the foregoing points, the printer is provided with a key to switch among the draft print, NLQ print, and the like and keys to switch the print pitch and line feed pitch. The printing mode and the other pitches are switched by these keys. Further, the apparatus is switched such that no command is input from the host computer. Only the data is received and executed by the apparatus.
The printing mode, pitch, and the like switched by the printer side are reset to the print mode, pitch, and the like in response to an initial signal and designation commands of the different printing mode, pitch, and the like which are output from the host computer. Therefore, the printing mode, pitch, and the like which are designated and input by the keys are cancelled.
In this case, when the user designates the printing mode, pitch, and the like by operating the keys, this means that the user wants to execute the printing on the basis of the printing mode and the like designated by the key inputs irrespective of the printing mode and the like designated by the host computer. Therefore, if the printing mode and the like designated by the user are switched by the commands which are generated from the host computer, an inconvenience will occur since the switched printing mode and the like are different from the user's requirements.
In particular, the pica pitch of 10 cpi and the draft printing mode are generally used in the printer (standard mode). When the print pitch and printing mode are designated by commands from the host computer, another pitch and printing mode are ordinarily designated by these commands. For example, in many cases, the operator desires to continuously print by designating the pitch of 12 cpi and NLQ mode.
Namely, it is demanded that the printer having advanced functions is further used in a desired mode designated at the printer (at the position of the user) or can be used in the mode which is designated at the host computer side. It is further demanded that such a printer can be easily and effectively used.
In such conventional recording apparatus, when an initial signal (INIT signal) to initialize the recording apparatus is input from the host side, a predetermined printing mode, print pitch, and the like are set similarly to the case when the power supply of the recording apparatus is turned on. Simultaneously, the print buffer, input buffer, flags, and the like are cleared and the I/O port is set.
On the other hand, in a recording apparatus whose function can be set by the keyboard, namely, in the recording apparatus in which the printing mode such as draft (ordinary printing), NLQ (near letter quality), or the like, the print pitch, and the like are merely designated by the keyboard without using commands from the host side, for example, in the case where the print output mode is limited for use in only the printer to output sentences, the function can be easily conveniently set from the keyboard. If the software is constituted in such a manner that, when inputting from the keyboard, the data is transferred from the host side after the initial signal is output, there is an inconvenience in that the printing mode which has previously been set from the keyboard is cleared. In addition, there is the problem that the operation becomes complicated, since the printing mode, print pitch, and the like must be reset every time the data is output.
On the other hand, in output formats from the host side, there is a format such that after the printer is once reset, a command is transferred. In the case of making the printer operative by such software, the problem which is caused in the case where the printing is controlled by the function of the keyboard is particulary likely to occur.